JP2004070348A - Polarizer, optical film using it, and image display using them - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polarizer capable of forming a liquid crystal display and an electroluminescence display showing excellent display characteristics with little display unevenness. <P>SOLUTION: This polarizer contains a dichroism substance in a matrix, having an in-plane phase difference in measuring wavelength showing no absorption in the range of 950-1,350 nm. The measuring wavelength is, for example, 1,000 nm, preferably for which the dichroism substance shows no absorption. <P>COPYRIGHT: (C)2004,JPO

Description

The present invention relates to a polarizer, an optical film such as a polarizing plate using the polarizer, and an image display device.

  Liquid crystal display devices (LCDs) are widely used in desktop electronic calculators, electronic watches, personal computers, word processors, instruments for automobiles and machines, and the like. Such a liquid crystal display device usually includes a polarizing plate for visualizing a change in the orientation of liquid crystal, and this polarizing plate has a very large effect on the display characteristics of the liquid crystal display device.

  As the polarizing plate, generally, a protective film such as triacetyl cellulose is laminated on both surfaces of a polarizer (polarizing film) such as a polyvinyl alcohol-based film in which a dichroic substance such as iodine or an organic dye is adsorbed and oriented. In particular, a polarizer which can provide a liquid crystal display device which is bright and has excellent display characteristics with good color reproducibility is desired.

  However, in the liquid crystal display device, particularly when a backlight that emits polarized light is used, there is a problem that display unevenness occurs and uniformity of contrast is reduced.

In order to solve such a problem, for example, a polarizing plate using a polyvinyl alcohol-based polymer film that can be easily stretched has been disclosed (for example, see Patent Document 1).
JP-A-14-028939

  However, when high contrast is realized in the image display device, there is a problem that display unevenness is conspicuously observed. For example, when the liquid crystal mode is normally black (a state in which no voltage is applied is a black display state), the effect is remarkable. In particular, when the liquid crystal mode is viewed from an oblique direction of 30 °, 40 °, or 60 ° or more, display unevenness occurs. There is a problem that becomes noticeable. For these reasons, various display devices, such as a liquid crystal display device, which exhibit no more display unevenness and exhibit uniform display characteristics are now desired.

The polarizer of the present invention is a polarizer containing a dichroic substance in a matrix, and has a characteristic feature that an in-plane retardation is in a range of 950 to 1350 nm at a measurement wavelength that does not show absorption.

The present inventors have found that the phase difference of the polarizer itself is involved in the above-mentioned display unevenness, and have conducted intensive research. As a result, if the in-plane phase difference at the measurement wavelength that does not show the absorption is in the range of 950 to 1350 nm, for example, even if the phase difference varies in the polarizer, the variation is hardly visible. Was found. In other words, even when a shade of blue due to uneven dyeing or the like is observed in the polarizer, the polarizer exhibiting an in-plane retardation as in the present invention exhibits a blue color when arranged in crossed nicols. Becomes a similar color to the blue of the phase difference itself, and the color unevenness becomes inconspicuous. For this reason, regardless of the presence or absence of a phase difference variation, when applied to various image display devices, especially large or high contrast display devices, and flat panel displays, display unevenness (particularly display unevenness in black display) is sufficiently reduced. It can be eliminated.

The polarizer of the present invention is a polarizer containing a dichroic substance in a matrix as described above, and has a characteristic feature that an in-plane retardation is in a range of 950 to 1350 nm at a measurement wavelength that does not show absorption. And The in-plane retardation is preferably set in a range of 1,050 to 1,250 nm, more preferably, 1,100 to 1,200 nm. The in-plane retardation (Δnd) is represented by the following equation, where nx and ny indicate the refractive indexes of the polarizer in the X-axis and Y-axis directions, respectively, and the X-axis indicates the polarization of the polarized light. The direction of the axis showing the maximum refractive index in the plane of the polarizer, the direction of the Y axis is an axis direction perpendicular to the X axis in the plane, and d represents the thickness of the polarizer.
Δnd = (nx−ny) · d
In the present invention, the in-plane retardation is, for example, the size of the polarizer is set to 8 to 800 cm × 15 to 1500 cm, every 1 to 20 mm vertically and horizontally, the phase difference at a total of 28 to 1,200,000 measurement points. When measured, all measured values are preferably included in the above range. As a specific example, when a phase difference is measured at a total of 12276 measurement points every 2 mm for a 25 cm × 20 cm polarizer, it is preferable that all the measured values fall within the above range.

The measurement wavelength is not particularly limited as long as the polarizer of the present invention does not exhibit absorption, that is, a wavelength at which the dichroic substance does not exhibit absorption, and is, for example, 800 to 1500 nm, and preferably 840 to 1200 nm. And particularly preferably 1000 nm. In setting the measurement wavelength, for example, when the measurement wavelength is x (nm), it is necessary to consider the chromatic dispersion ΔRx represented by the following equation. In the case of the absorption edge and x _a, it is necessary that x> x _a.

　本発明の偏光子は、さらに、前記吸収を示さない測定波長において、面内位相差の微分位相差変化量（σ）が、−５ｎｍ／ｍｍ〜５ｎｍ／ｍｍの範囲であることが好ましい。微分位相差変化量（σ）が、このような範囲であれば、例えば、特にＬＣＤテレビ等の大画面ディスプレイにおいて、高い均一性を示すという効果を奏する。微分位相差変化量（σ）は、より好ましくは−４ｎｍ／ｍｍ〜４ｎｍ／ｍｍの範囲、特に好ましくは−２．５ｎｍ／ｍｍ〜２．５ｎｍ／ｍｍの範囲である。

It is preferable that the polarizer of the present invention further has a differential phase difference change amount (σ) of the in-plane retardation in a range of −5 nm / mm to 5 nm / mm at the measurement wavelength not exhibiting the absorption. When the differential phase difference change amount (σ) is in such a range, for example, an effect of exhibiting high uniformity is exhibited particularly in a large-screen display such as an LCD television. The differential phase difference change amount (σ) is more preferably in the range of −4 nm / mm to 4 nm / mm, and particularly preferably in the range of −2.5 nm / mm to 2.5 nm / mm.

The “differential phase difference change amount (σ)” is a difference (ΔR = R _i −R _{i +} ) between the phase differences (R _i , R _{i + 1} ) at two measurement points (i, i + 1). ₁ ) and the distance d (mm) between the two measurement points, and is represented by σ = ΔR / d.

距離 The distance between the measurement points is preferably 1 to 100 mm, more preferably 3 to 70 mm, from the viewpoint of accurately determining a locally occurring phase difference change.

The polarizer of the present invention, at the measurement wavelength that does not show the absorption, when the in-plane phase difference shows a maximum value and a minimum value, respectively, the distance between the measurement site showing the maximum value and the measurement site showing the minimum value, For example, it is 10 mm or less (exceeding 0) or 100 mm or more, and the difference (in-plane retardation variation) between the maximum value and the minimum value is less than 60 nm. Preferably, the distance is 7 mm or less or 120 mm or more, and the in-plane retardation variation is less than 45 nm, more preferably, the distance is 5 mm or less or 150 mm or more, and the in-plane retardation variation is less than 45 nm. It is. If the distance is as short as 10 mm or less, the local maximum value and the local minimum value are very close to each other, so that it is difficult to see the variation in the phase difference. However, among them, if the distance is long, the dispersion of the in-plane retardation becomes gentle, and the retardation variation of the polarizer becomes more difficult to see, so that it is more preferably 100 mm or more, and particularly preferably 150 mm or more. is there. The upper limit of the distance is not limited and corresponds to the size of the film.

  Such a polarizer of the present invention is applied to, for example, a polarizing plate or an optical film, and is further used for various image display devices such as a liquid crystal display device. Therefore, for example, the polarizer may be cut in advance (so-called “chip cut”) according to the size of the liquid crystal cell or the like.

偏光 Such a polarizer of the present invention can be produced, for example, by subjecting a polymer film to a swelling treatment, a dyeing treatment with a dichroic substance, a crosslinking treatment, a stretching treatment, a water washing treatment, or the like, as described below. In addition, the present invention is characterized in that, among polarizers, the in-plane retardation is selected within the above range, and the production itself of a polarizer satisfying the in-plane retardation is known to those skilled in the art at the time of filing. It can be performed based on common technical knowledge.

(1) Polymer film The polymer film is not particularly limited, and a conventionally known film can be used. For example, a polyvinyl alcohol (PVA) film, a partially formalized PVA film, polyethylene terephthalate (PET), ethylene Examples include hydrophilic polymer films such as vinyl acetate copolymer films and partially saponified films thereof. In addition to these, a polyene oriented film such as a PVA dehydrated product or a polyvinyl chloride dehydrochlorinated product, and a stretch-oriented polyvinylene-based film can also be used. Among these, a PVA-based polymer film is preferable because of its excellent dyeability with the dichroic substance iodine. In the polymer film, the length in the stretching direction is hereinafter referred to as “length”, and the length in the direction perpendicular to the stretching direction is referred to as “width”.

The degree of polymerization of the PVA film is preferably, for example, in the range of 1700 to 4500, more preferably 2400 to 4000, and the crystallinity is preferably in the range of 18 to 50%, more preferably 23-47%. Further, the glycerin content of the film is, for example, preferably in the range of 7 to 20% by weight, and more preferably in the range of 8 to 18% by weight.

The thickness of the polymer film is not particularly limited, but is preferably, for example, in the range of 65 to 80 μm, and more preferably 70 to 85 μm.

The polymer film, for example, the local thickness variation is preferably 0.7 μm / cm or less with respect to the average thickness, more preferably 0.5 μm / cm or less, particularly preferably 0.2 μm / cm It is as follows. Further, even in the case of a polymer film in which the thickness variation exceeds 0.7 μm / cm, for example, by swelling treatment described later, crosslinking treatment, or by optimizing a stretching treatment, or by controlling liquid drainage, The effect of the thickness variation can be avoided.

Here, “the local thickness variation is 0.7 μm / cm or less with respect to the average thickness” is, for example, the thickness variation between two points 1 to 100 mm apart, that is, “the two points described above. Thickness difference / distance between two points ”is 0.7 μm / cm or less. The average thickness is not particularly limited. For example, in the case of a PVA-based film (raw material) having a maximum width of 2600 mm, 2600 points may be measured. Note that the present invention is not limited to this.

、 As the polymer film, for example, it is preferable to use a film that has little swelling variation, that is, a thickness variation due to swelling in the swelling treatment in the next step. This is because, for the polarizer manufactured in this way, for example, variations in retardation, dichroic substance content, transmittance, and the like can be further reduced. For this reason, for example, it is preferable to use a polymer film having less crystallinity unevenness, thickness unevenness, and variation in moisture content. Further, a polymer film having no variation in glycerin content is also preferable.

(2) Swelling treatment The polymer film is dipped in a swelling bath to be swollen, and subjected to a stretching treatment in the swelling bath.

  As the solution of the swelling bath, for example, water, an aqueous glycerin solution, an aqueous potassium iodide solution and the like can be used. The conditions for the swelling treatment are not particularly limited, and the swelling treatment can be carried out in the same manner as in the conventional case. Seconds). When the swelling time is 60 seconds or longer, for example, the contamination of the dyeing bath in the subsequent dyeing step can be sufficiently avoided, so that the problem of long run property can be reduced and the dyeing unevenness can be sufficiently prevented. Further, when the swelling time is 300 seconds or less, the occurrence of breakage during stretching in the subsequent stretching step can be sufficiently suppressed.

浸漬 By immersion in the swelling bath, the polymer film swells usually 1.1 to 1.5 times the length of the film (raw material) before swelling. Further, it is preferable to perform a stretching treatment in the swelling bath to 1 to 1.3 times (preferably 1.05 to 1.25 times) the swelling amount.

In the swelling step, when the stretching ratio is reduced and the immersion time is lengthened, in order to remove wrinkles generated in the film, for example, rolls such as an expander roll, a spiral roll, and a crown roll are provided in the swelling bath. Is preferred. In particular, when the width of the web is long (for example, when the width exceeds about 3 m), it is preferable to install a roll to remove wrinkles at the center of the web.

As described above, the polymer film preferably has a small swelling variation. Specifically, the thickness variation after swelling is preferably 8% or less, more preferably 5% or less, and particularly preferably 2.5% or less. It is. This is because, when the polymer film is swollen, there is a difference in swelling and elongation due to the swelling due to the thickness variation. Specifically, it is considered that the thinner the thickness is, the more swelling causes the elongation, and the larger the thickness is, the harder the elongation is. Since the thinner part of the film swells as described above, it is preferable to swell the film slowly in order to saturate the film.

フ ィ ル ム In the film, it is preferable that the difference between the maximum value and the minimum value of the thickness and the distance between the portion having the maximum value and the portion having the minimum value have the following relationship. That is, “(difference between maximum value and minimum value) / distance” is, for example, 1.5 μm / cm or less, preferably 1.0 μm / cm or less, and more preferably 0.5 μm / cm or less. In particular, the distance is preferably 5 mm or less or 250 mm or more, more preferably 10 mm or less or 150 mm or more, and particularly preferably 20 mm or less or 100 mm or less. This is, for example, in the stretching process and drying process described later, by contracting the portion showing the maximum thickness, it is sufficient to be stretched slightly in the direction perpendicular to the stretching direction (TD direction) of the site showing the minimum thickness. This is because it can be prevented. Further, if the distance is 10 mm or less, the uneven dyeing is less noticeable because the distance is small, and if it is 250 mm or more, the stretching of the maximum value portion and the minimum value portion is performed gently, as described above. This is because the stretching in the vertical direction due to the shrinkage can be sufficiently prevented.

(2) Dyeing treatment The polymer film is pulled up from the swelling bath, immersed in, for example, a dyeing bath containing a dichroic substance, and further stretched uniaxially in the dyeing bath. That is, the dichroic substance is adsorbed on the polymer film by the immersion, and the dichroic substance is oriented in one direction by stretching.

  As the dichroic substance, conventionally known substances can be used, and examples thereof include iodine and organic dyes. When using the organic dye, for example, it is preferable to combine two or more types from the viewpoint of neutralizing the visible light region.

  As the solution of the dye bath, an aqueous solution in which the dichroic substance is dissolved in a solvent can be used. As the solvent, for example, water can be used, but an organic solvent compatible with water may be further added. The concentration of the dichroic substance in the solution is not particularly limited, but is usually in the range of 0.005 to 0.10% by weight, preferably 0.01 to 0.08% by weight.

  The immersion time of the polymer film in the dye bath is not particularly limited, but is, for example, in the range of 30 to 120 seconds, preferably 40 to 110 seconds, and more preferably 50 to 100 seconds. The temperature of the dyeing bath is usually from 10 to 35 ° C.

  The stretching magnification in this dyeing treatment is, for example, preferably in the range of 2 to 3.2 times, more preferably 2.2 to 3.1 times the length of the polymer film (raw material) before swelling. And especially preferably 2.4 to 3.0 times. If the stretching ratio is 2 times or more, for example, the generation of ripples in the stretching direction (MD direction) of the film is sufficiently suppressed and there is no problem of uneven dyeing, and if it is 3.2 times or less, A sufficient degree of polarization can be maintained.

  If wrinkles occur in the polymer film, it may cause uneven dyeing, so in the dyeing bath, for example, various rolls as described above are arranged, and even if wrinkles generated in the polymer film are removed by them. Good. Before or after the polymer film is immersed in the dyeing bath, wrinkles may be eliminated by the roll.

(3) Crosslinking treatment The polymer film is pulled out of the dyeing bath, immersed in a crosslinking bath containing a crosslinking agent, and further stretched in the crosslinking bath. The running stability is maintained by performing the crosslinking treatment.

  As the crosslinking agent, a conventionally known substance can be used, and examples thereof include boron compounds such as boric acid, borax, glyoxal, and glutaraldehyde. These may be used alone or in combination of two or more. As the solution of the crosslinking bath, an aqueous solution in which the crosslinking agent is dissolved in a solvent can be used. As the solvent, for example, water can be used, and it may further contain an organic solvent compatible with water.

  The concentration of the crosslinking agent in the solution is not particularly limited, but is usually in the range of 1 to 10% by weight, preferably 1.5 to 8% by weight. When the crosslinking agent is boric acid, for example, it is in the range of 1.5 to 7% by weight, preferably 2 to 6% by weight.

  The aqueous solution, in addition to the boric acid compound, for example, potassium iodide, lithium iodide, sodium iodide, zinc iodide, aluminum iodide, iodine An auxiliary agent such as iodide such as lead iodide, copper iodide, barium iodide, calcium iodide, tin iodide, and titanium iodide may be contained. The content of the auxiliary agent in the solution is usually in the range of 1 to 18% by weight, preferably 2 to 18% by weight. When the auxiliary is potassium iodide, it is in the range of 2 to 15% by weight, preferably 5 to 14% by weight.

  Above all, a combination of boric acid and potassium iodide is preferable, and the ratio (weight ratio) of boric acid to potassium iodide in the solution is, for example, usually in the range of 7: 1 to 1: 9, preferably 5: 1. It is in the range of 1-1: 5.

温度 The temperature of the crosslinking bath is not particularly limited. For example, it is preferable that the relationship between the temperature of the dyeing treatment and the temperature of the crosslinking treatment described below satisfies “dyeing temperature <crosslinking temperature ≦ stretching temperature”. Specifically, the range is preferably from 8 to 75 ° C, more preferably from 20 to 70 ° C. The immersion time of the polymer film is not particularly limited, but is usually 25 to 150 seconds, preferably 30 to 120 seconds.

  The stretching ratio in this crosslinking treatment is, for example, 3.5 times or less, and preferably 3.3 times or less with respect to the length of the raw fabric.

(4) Stretching The polymer film is pulled out of the crosslinking bath, immersed in a final stretching bath, and further stretched in the stretching bath. Note that the crosslinking treatment and the stretching treatment may be further repeated.

  The solution of the stretching bath is not particularly limited, and for example, a solution containing boric acid, potassium iodide, various metal salts, other iodide compounds, zinc compounds, and the like can be used. As a solvent for this solution, for example, water, ethanol, or the like can be used.

Specifically, when boric acid is used, its concentration is usually in the range of 2 to 10% by weight, preferably 3 to 6% by weight. The boric acid concentration in the stretching bath is preferably higher than the boric acid concentration in the crosslinking bath. Further, it is preferable to use potassium iodide in combination. In this case, for example, it is preferable to set the concentration higher than the concentration of potassium iodide in the above-mentioned crosslinking bath. The concentration of the potassium iodide is usually in the range of 4 to 10% by weight, preferably 6 to 8% by weight. In addition, it is preferable that the concentration of potassium iodide in the stretching bath is set higher than, for example, the concentration of potassium iodide in the crosslinking bath.

温度 The temperature of the stretching bath is usually in the range of 40 to 75 ° C, preferably 50 to 70 ° C.

  The stretching ratio in this stretching process is, for example, in the range of 5.5 to 6.5 times, preferably in the range of 5.8 to 6.4 times, more preferably 6. The range is 0 to 6.2 times.

The stretching time is, for example, preferably from 35 seconds to 60 seconds, and more preferably from 40 seconds to 50 seconds.

(5) Rinsing treatment The polymer film is pulled out of the stretching bath, immersed in an iodide-containing aqueous solution, washed with water, and dried.

ヨ As the iodide in the iodide-containing aqueous solution, those described above can be used, and among them, potassium iodide, sodium iodide and the like are preferable. Usually, water can be used as this solvent. With this iodide-containing aqueous solution, the remaining boric acid used in the stretching treatment can be washed out of the polymer film.

When the aqueous solution is a potassium iodide aqueous solution, its concentration is, for example, preferably in the range of 0.5 to 20% by weight, more preferably 1 to 15% by weight, and particularly preferably 1.5 to 15% by weight. 7% by weight. The temperature of the aqueous solution is usually in the range of 15 to 40 ° C, preferably 20 to 35 ° C. The immersion time in the aqueous solution is usually 2 to 15 seconds, preferably 3 to 12 seconds. In addition, the number of times of water washing after immersion in the iodide-containing aqueous solution is not particularly limited.

に お い て At this stage, the width and thickness of the stretched polymer film preferably satisfy the following conditions. By satisfying the following conditions, the manufactured polarizer of the present invention has further improved neutrality. Specifically, when the polarizer or the polarizing plate using the polarizer of the present invention is arranged in parallel Nicols, the yellow tint can be further suppressed, and when the polarizers are orthogonally arranged, the blue tint or red tint can be obtained. Can be further suppressed.

That is, when the total stretching ratio (magnification with respect to the raw material) of the stretching performed so far is a (hereinafter the same), the width of the stretched polymer film is the width of the polymer film (raw material) before swelling. 100%, the range is (1 / √a × 100)% to (1 / √a × 125)%, preferably (1 / √a × 100)% to (1 / √a × 120)% More preferably, it is preferably (1 / に a × 100)% to (1 / √a × 110)%. Specifically, when the stretching ratio a is 6, the ratio is preferably 41 to 51%, more preferably 41 to 45%. In addition, the width of the polymer film is a length in a direction perpendicular to the stretching direction (length direction) as described above.

勾 配 In addition, when the stretched polymer film is not stretched uniformly, for example, a gradient may occur in its thickness. In that case, in the stretched polymer film, the thinnest part is (1 / √a × 80)% to (1 / √a × 100)%, preferably (1√ It is preferable that the deformation is from (/ √a × 85)% to (1 / √a × 100)%, more preferably (1 / √a × 90)% to (1 / √a × 100)%. This is because it is preferable to increase Δn by a high stretching ratio and further increase the thickness d. Also, the thinnest part of the film tends to become thinner due to shrinkage of the periphery and other parts in the width direction, so that the uniaxiality is reduced, the optical properties are locally reduced, and unevenness may be remarkable. Because there is.

Further, in the stretched polymer film, it is preferable that the width and the thickness satisfy the following relationship. That is, the value represented by the following formula (I) is, for example, in the range of 0.9 to 1.1, and preferably in the range of 0.95 to 1.05.

_{(T b × W b) /} (T a × W a) ··· (I)
The average thickness W _a width W _b unstretched polymer film of stretched polymer film (raw) width (6) drying process the polymer was carried out as described above having an average thickness T _b unstretched polymer film T _a stretched polymer film By drying the film, the polarizer of the present invention containing the dichroic substance in the matrix can be produced. Drying is not particularly limited, for example, natural drying, air drying, heating drying, etc., but in the case of heating drying, the temperature is usually 20 to 40 ° C, preferably 22 to 35 ° C. The processing time is usually in the range of 0.5 to 5 minutes, preferably 1 to 4 minutes, more preferably 1.5 to 3 minutes.

  Although the thickness of the finally obtained polarizer of the present invention is not particularly limited, it is, for example, preferably in the range of 5 to 40 μm, more preferably 15 to 35 μm, and particularly preferably 17 to 32 μm. When the thickness is 5 μm or more, for example, it shows more excellent mechanical strength, and when it is 40 μm or less, it has more excellent optical properties. It becomes easy.

In addition to the polarizer manufactured by the above method, as long as the above-mentioned in-plane retardation is exhibited, for example, a film obtained by kneading a dichroic substance into PET or the like, forming a film, and stretching the film may be used. Then, a stretched and oriented polyvinylene-based film or a film obtained by kneading a dichroic substance into the film may be used as the polarizer. In addition, an O-type polarizer (U.S. Pat. No. 5,523,863, Japanese Patent Publication No. 3-503322) in which a liquid crystal oriented in a uniaxial direction is used as a host and a dichroic dye is used as a guest there, and An E-type polarizer using a dichroic lyotropic liquid crystal or the like may be used (US Pat. No. 6,049,428).

Next, the optical film of the present invention contains the polarizer of the present invention. Examples of such an optical film are shown below.

A first example of the optical film of the present invention includes, for example, a polarizing plate including the polarizer of the present invention and a transparent protective layer, wherein the transparent protective layer is disposed on at least one surface of the polarizer. . The transparent protective layer may be disposed on only one surface of the polarizer, or may be disposed on both surfaces. When laminating on both sides, for example, the same type of transparent protective layer may be used, or different types of transparent protective layers may be used.

When measuring the in-plane retardation of the polarizer in the polarizing plate, the measurement can be performed by removing the transparent protective layer from the polarizing plate of the present invention using, for example, a solvent or the like. In the case where the retardation of the transparent protective layer is within a negligible range (approximately 0 nm), the measurement can be performed with the polarizing plate.

In the polarizing plate of the present invention, for example, since the width changes depending on the moisture content, the moisture content is, for example, preferably 2 to 5%, more preferably 2.5 to 4.5%, and particularly preferably 3 to 5%. It is in the range of 4%.

  FIG. 1 shows a cross-sectional view of an example of the polarizing plate. As illustrated, the polarizing plate 10 includes a polarizer 1 and two transparent protective layers 2, and the transparent protective layers 2 are disposed on both surfaces of the polarizer 1.

  The transparent protective layer 2 is not particularly limited, and a conventionally known transparent protective film can be used. For example, those having excellent transparency, mechanical strength, heat stability, moisture barrier properties, isotropy, and the like are preferable. . Specific examples of the material of such a transparent protective layer include cellulose resins such as triacetyl cellulose, polyester, polycarbonate, polyamide, polyimide, polyethersulfone, polysulfone, polystyrene, and acrylic. And transparent resins such as acetate, polyolefin and the like. Further, there may be mentioned a thermosetting resin such as acrylic, urethane, acrylic urethane, epoxy and silicone, or an ultraviolet curable resin. Further, a resin having a low photoelastic coefficient, such as a polynobornene-based resin, is also preferable.

In addition, as described in JP-A-2001-343529 (WO 01/37007) and JP-A-2002-328233, for example, an alternating copolymer comprising isobutene and N-methylmaleimide is used. A film made of a mixed extrudate of a resin composition containing acrylonitrile / styrene copolymer can also be used. Such a film can be manufactured, for example, as described below. First, the alternating copolymer (100 parts by weight) having an N-methylmaleimide content of 50 mol% and 67 parts by weight of the acrylic copolymer having a tolyl content of 27 wt% and a styrene content of 73 wt% were melt-kneaded. The pellets are supplied to a melt extruder equipped with a T die to produce a raw film. This film is subjected to free-end longitudinal uniaxial stretching at a stretching speed of 100 cm / min, a stretching ratio of 1.45 times, and a stretching temperature of 162 ° C. Further, by performing uniaxial stretching at the free end in the direction perpendicular to the stretching direction under the same conditions, a stretched film having a thickness of 49 μm is obtained. This stretched film has nx = 1548028, ny = 1.548005, nz = 1.547970, an in-plane retardation of 1.1 nm, a thickness direction retardation of 2.8 nm, and an absolute value of the photoelastic coefficient of 1.9 × 10-13 cm ² / dye.

Furthermore, the surfaces of these transparent protective films may be saponified with an alkali or the like, for example. Among these, a TAC film is preferable in terms of polarization characteristics and durability, and more preferably a TAC film whose surface is saponified.

It is preferable that the transparent protective layer has no coloring, for example. Specifically, the retardation value (Rth) in the film thickness direction represented by the following formula is preferably in the range of -90 nm to +75 nm, more preferably -80 nm to +60 nm, and particularly preferably -70 nm. ＋+ 45 nm. When the retardation value is in the range of -90 nm to +75 nm, coloring (optical coloring) of the polarizing plate caused by the protective film can be sufficiently eliminated.
Rth = [{(nx + ny) / 2} -nz] · d
In the above formula, d is the thickness of the transparent protective layer, and nx, ny, and nz indicate the X-, Y-, and Z-axis refractive indexes of the transparent protective layer, respectively. The X axis is an axis direction showing the maximum refractive index in the plane of the transparent protective layer, the Y axis is an axis direction perpendicular to the X axis in the plane, and the Z axis is the X axis. The thickness direction perpendicular to the axis and the Y axis is shown.

  The thickness of the transparent protective layer is not particularly limited, but is, for example, 500 μm or less, preferably 1 to 300 μm, more preferably 5 to 300 μm, for the purpose of reducing the thickness of the polarizing plate. .

  Further, the transparent protective layer may be further subjected to, for example, a hard coat treatment, an antireflection treatment, an anti-sticking treatment, a treatment for the purpose of diffusion, antiglare, or the like. The hard coat treatment is for the purpose of preventing scratches on the surface of the polarizing plate and the like, for example, a process of forming a cured film made of a curable resin and having excellent hardness and slipperiness on the surface of the transparent protective layer. It is. As the curable resin, for example, an ultraviolet curable resin such as a silicone-based, urethane-based, acrylic-based, or epoxy-based resin can be used, and the treatment can be performed by a conventionally known method.

  The antireflection treatment is intended to prevent reflection of external light on the surface of the polarizing plate, and can be performed by forming a conventionally known antireflection film or the like. The purpose of the anti-sticking treatment is to prevent adhesion between adjacent layers.

  The anti-glare treatment is to reflect external light on the surface of the polarizing plate, to prevent obstruction of light transmitted through the polarizing plate, and the like.For example, by a conventionally known method, the surface of the transparent protective layer is finely divided. This can be performed by forming an uneven structure. Examples of the method of forming such a concavo-convex structure include a method of forming a surface by sandblasting or embossing, and a method of forming the transparent protective layer by blending transparent fine particles with the transparent resin as described above. Can be

The transparent fine particles include, for example, silica, alumina, titania, zirconia, tin oxide, indium oxide, cadmium oxide, antimony oxide, and solid solutions thereof. The average particle size of such transparent fine particles is not particularly limited, but is, for example, in the range of 0.5 to 50 μm. In addition, inorganic fine particles having conductivity, organic fine particles composed of crosslinked or uncrosslinked polymer particles, and the like can also be used. The blending ratio of the transparent fine particles is not particularly limited, but is generally preferably in the range of 2 to 50 parts by mass, more preferably in the range of 5 to 25 parts by mass per 100 parts by mass of the transparent resin as described above.

The anti-glare layer containing the transparent fine particles can be used, for example, as the transparent protective layer itself, or may be formed as a coating layer on the surface of the transparent protective layer. Further, the anti-glare layer may also serve as a diffusion layer for diffusing light transmitted through the polarizing plate to increase the viewing angle.

  In addition, the antireflection film, the diffusion layer, the antiglare layer, and the like can be provided on the polarizing plate separately from the transparent protective layer, for example, as an optical layer including a sheet provided with these layers.

方法 The method of bonding the polarizer and the transparent protective layer is not particularly limited, and can be performed by a conventionally known method. Generally, an adhesive or other adhesive is used, and the type can be appropriately determined depending on the type of the polarizing film or the transparent protective layer. Specific examples include adhesives and pressure-sensitive adhesives composed of PVA-based, modified PVA-based, and urethane-based polymers. These adhesives and the like, for the purpose of improving durability, for example, a vinyl alcohol-based polymer such as boric acid, borax, glutaraldehyde, melamine, oxalic acid, chitin, chitosan, metal salts, alcohol-based solvents, etc. A water-soluble crosslinking agent for crosslinking may be added. When the polarizer is, for example, a PVA-based film, a PVA-based adhesive is preferable from the viewpoint of the stability of the bonding treatment and the like. The thickness of such an adhesive layer is not particularly limited, but is, for example, 1 nm to 500 nm, preferably 10 nm to 300 nm, and more preferably 20 nm to 100 nm.

When the polarizer and the transparent protective layer are adhered by the adhesive, for example, a drying treatment is performed to prevent the polarizer from peeling off due to the influence of humidity or heat and to obtain a polarizing plate having excellent light transmittance and degree of polarization. Is preferably applied. The drying temperature is not particularly limited, and can be appropriately determined according to the type of the adhesive or the pressure-sensitive adhesive used. When the pre-adhesive is a water-soluble adhesive such as a PVA-based, modified PVA-based, or urethane-based adhesive described above, for example, the drying temperature is preferably from 60 to 70 ° C, more preferably from 60 to 75 ° C, The drying time is preferably about 1 to 10 minutes.

  Further, for example, the polarizing plate of the present invention preferably further has a pressure-sensitive adhesive layer as the outermost layer, since it can be easily laminated on a liquid crystal cell or the like. FIG. 2 shows a cross-sectional view of a polarizing plate having such an adhesive layer. As shown, the polarizing plate 20 includes the polarizing plate 10 and the pressure-sensitive adhesive layer 3 shown in FIG. 1, and the pressure-sensitive adhesive layer 3 is further disposed on the surface of one of the transparent protective layers 2 of the polarizing plate 10. .

The formation of the pressure-sensitive adhesive layer on the surface of the transparent protective layer, for example, by directly adding a solution or melt of the pressure-sensitive adhesive to a predetermined surface of the transparent protective layer by a developing method such as casting or coating. It can be carried out by a method of forming a layer, a method of forming an adhesive layer on a separator similarly described later, and transferring the pressure-sensitive adhesive layer to a predetermined surface of the transparent protective layer. In addition, such an adhesive layer may be formed on any one surface of the polarizing plate as shown in FIG. 2, but is not limited thereto, and may be arranged on both surfaces as necessary. .

  The pressure-sensitive adhesive layer can be formed by appropriately using, for example, a conventionally known pressure-sensitive adhesive such as an acrylic, silicone, polyester, polyurethane, polyether, or rubber. In particular, the moisture absorption rate is low in terms of prevention of foaming and peeling phenomena due to moisture absorption, prevention of deterioration of optical characteristics and warpage of liquid crystal cells due to differences in thermal expansion, and formation of a liquid crystal display device having high quality and excellent durability. It is preferable to use an adhesive excellent in heat resistance. Examples of such an adhesive include acrylic, silicone, acrylic silicone, polyester, and heat-resistant rubber adhesives. Further, it may be an adhesive layer containing fine particles and exhibiting light diffusibility.

  When the surface of the pressure-sensitive adhesive layer provided on the polarizing plate is exposed, the surface is preferably covered with a separator for the purpose of preventing contamination and the like until the pressure-sensitive adhesive layer is put to practical use. The separator may be provided with a release coat using a release agent such as a silicone-based, long-chain alkyl-based, fluorine-based, or molybdenum sulfide, as necessary, on an appropriate thin film such as the transparent protective film. Can be formed.

The thickness of the pressure-sensitive adhesive layer is not particularly limited, but is preferably, for example, 5 to 35 μm, more preferably 10 to 25 μm, and particularly preferably 15 to 25 μm. By setting such a range, for example, even if the dimensions of the polarizing plate change, the stress generated at that time can be reduced.

  The polarizing plate of the present invention can be used for forming a liquid crystal cell, a liquid crystal display device, or the like. For example, in a state where a transparent protective layer or the like is laminated on the polarizer, cutting is performed according to the size of the liquid crystal cell or the like. (Chip cutting), or the polarizer may be cut in advance, and then a transparent protective layer may be attached.

  Next, a second example of the optical film of the present invention is a laminate including the polarizer of the present invention or the polarizing plate of the first example, and at least one of a polarization conversion element and a retardation film.

  The polarization conversion element is not particularly limited, and examples thereof include those generally used for forming a liquid crystal display device and the like, such as an anisotropic reflection type polarization element and an anisotropic scattering type polarization element. These polarization conversion elements may be, for example, one layer or two or more layers. When two or more layers are used, the same kind or different kinds of layers may be used.

  Among the polarization conversion elements, the anisotropic reflection-type polarizing element is, for example, a composite of a cholesteric liquid crystal layer and a retardation plate, and the retardation plate has a reflection property of the anisotropic reflection polarizer. It is preferable to show a phase difference of 0.2 to 0.3 times the wavelength included in the band. More preferably, it is 0.25 times. As the cholesteric liquid crystal layer, in particular, an oriented film of a cholesteric liquid crystal polymer, such as one in which the oriented liquid crystal layer is supported on a film substrate, or the like, reflects either left-handed or right-handed circularly polarized light. In addition, it is preferable that other light transmit the light. As such an anisotropic reflective polarizer, for example, a PCF series manufactured by Nitto Denko or the like can be used. The wavelength may be any wavelength as long as it is included in the reflection band of the anisotropic reflective polarizer. The cholesteric liquid crystal layer transmits linearly polarized light having a predetermined polarization axis and reflects other light, such as a multilayer thin film of a dielectric or a multilayer laminate of thin films having different refractive index anisotropies. It may be one that shows the characteristics of As such an anisotropic reflective polarizing element, for example, DBEF series manufactured by 3M Company or the like can be used.

  As the anisotropic reflection-type polarizing element, a reflection-type grid polarizer is also preferable, and as a specific example, MicroWires (trade name, manufactured by Moxtek) can be used.

  On the other hand, as the anisotropic scattering type polarizing element, for example, a trade name DRPF manufactured by 3M can be used.

  Next, a third example of the optical film of the present invention includes, for example, the polarizer of the present invention, the polarizing plate of the first example, or the laminate of the second example, and various optical layers. Various polarizing plates which are laminates are exemplified. The optical layer is not particularly limited. For example, a retardation plate including a λ plate such as a reflector, a semi-transmissive reflector, a 波長 wavelength plate, a 波長 wavelength plate, or the like, as described below, a viewing angle Examples include optical layers used for forming liquid crystal display devices and the like, such as compensation films and brightness enhancement films. One kind of these optical layers may be used, or two or more kinds may be used in combination. As the polarizing plate including such an optical layer, in particular, a reflective polarizing plate, a transflective polarizing plate, an elliptically polarizing plate, a circular polarizing plate, a polarizing plate on which a viewing angle compensation film or a brightness enhancement film is laminated, and the like are preferable. .

  Hereinafter, these polarizing plates will be described.

  First, an example of the reflective polarizing plate or the transflective polarizing plate of the invention will be described. The reflective polarizing plate is, for example, a reflective plate is further laminated on the polarizing plate of the first example as described above, the semi-transmissive reflective polarizing plate, the semi-transmissive reflective plate further has a semi-transmissive reflective plate. It is laminated.

The reflective polarizer is usually disposed on the back side of a liquid crystal cell, and can be used for a liquid crystal display device (reflective liquid crystal display device) that reflects incident light from the viewing side (display side) to display. Such a reflective polarizer can omit the incorporation of a light source such as a backlight, for example, and thus has advantages such as enabling the liquid crystal display device to be thinner.

  The reflection type polarizing plate can be manufactured by a conventionally known method such as a method of forming a reflection plate made of metal or the like on one surface of the polarizing plate after the heat treatment. Specifically, for example, one surface (exposed surface) of the transparent protective layer in the polarizing plate is subjected to a mat treatment as necessary, and a metal foil or a vapor-deposited film made of a reflective metal such as aluminum is coated on the surface. And the like.

  In addition, as described above, a reflective polarizing plate and the like, in which a reflective plate reflecting the fine uneven structure is formed on a transparent protective layer having a fine uneven structure on the surface by incorporating fine particles in various transparent resins as described above, may also be used. Can be A reflector having a fine uneven structure on its surface has an advantage that, for example, incident light is diffused by irregular reflection, directivity and glare can be prevented, and uneven brightness can be suppressed. Such a reflection plate, for example, on the uneven surface of the transparent protective layer, a vacuum deposition method, an ion plating method, a deposition method such as a sputtering method or a plating method, a conventionally known method, directly, the metal foil or It can be formed as a metal deposition film.

  Further, instead of a method in which the reflective plate is directly formed on the transparent protective layer of the polarizing plate as described above, a reflective sheet or the like provided with a reflective layer on an appropriate film such as the transparent protective film is used as the reflective plate. May be. Since the reflection layer in the reflection plate is usually made of metal, for example, to prevent a decrease in reflectance due to oxidation, and thus a long-lasting initial reflectance, and in order to avoid separately forming a transparent protective layer, It is preferable that the mode of use is such that the reflection surface of the reflection layer is covered with the film, the polarizing plate, or the like.

  On the other hand, the transflective polarizing plate has a transflective reflecting plate in place of the reflecting plate in the reflecting type polarizing plate. Examples of the semi-transmissive reflection plate include a half mirror that reflects light on a reflection layer and transmits light.

  The transflective polarizing plate is usually provided on the back side of a liquid crystal cell. When a liquid crystal display device or the like is used in a relatively bright atmosphere, it reflects incident light from the viewing side (display side) to form an image. In a relatively dark atmosphere for display, the present invention can be used for a liquid crystal display device or the like that displays images using a built-in light source such as a backlight built in the back side of a transflective polarizing plate. That is, the transflective polarizing plate can save energy for use of a light source such as a backlight in a bright atmosphere, and can be used with the built-in light source even in a relatively dark atmosphere. It is useful for formation of etc.

  Next, an example of the elliptically polarizing plate or the circularly polarizing plate of the present invention will be described. In these polarizing plates, for example, a retardation plate or a λ plate is further laminated on the polarizing plate of the first example as described above.

When the elliptically polarizing plate compensates (prevents) coloring (blue or yellow) caused by birefringence of a liquid crystal layer of a super twisted nematic (STN) type liquid crystal display device, for example, to provide a monochrome display without coloring. It is effectively used for such purposes. Further, an elliptically polarizing plate having a controlled three-dimensional refractive index is preferable because, for example, coloring that occurs when a screen of a liquid crystal display device is viewed from an oblique direction can be compensated (prevented). On the other hand, the circularly polarizing plate is effective for, for example, displaying an image in color, adjusting the color tone of an image of a reflective liquid crystal display device, and has an antireflection function.

The retardation plate is used for converting linearly polarized light to elliptically polarized light or circularly polarized light, for converting elliptically polarized light or circularly polarized light to linearly polarized light, or for polarizing the direction of linearly polarized light. In particular, as a retardation plate for converting linearly polarized light into elliptically polarized light or circularly polarized light and elliptically polarized light or circularly polarized light into linearly polarized light, for example, a quarter-wave plate (also referred to as “λ / 4 plate”) or the like is used. In the case where the polarization direction of the linearly polarized light is used, a 波長 wavelength plate (also referred to as a “λ / 2 plate”) is usually used.

As the material of the retardation plate, for example, polycarbonate, PVA, polystyrene, polymethyl methacrylate, polypropylene and other polyolefins, polyarylate, polyamide, birefringent film obtained by stretching a polymer film such as polynorbornene, a liquid crystal polymer Examples include an alignment film and a laminate in which an alignment layer of a liquid crystal polymer is supported by a film.

  Types of the retardation plate include, for example, various wavelength plates such as the １ ／ and ４, and those for the purpose of compensating for coloring due to birefringence of a liquid crystal layer and compensating for a viewing angle such as expansion of a viewing angle. A film having a phase difference according to the purpose may be used, or an obliquely oriented film having a controlled refractive index in the thickness direction may be used. Further, a laminated body in which two or more kinds of retardation plates are laminated and optical characteristics such as retardation are controlled may be used.

  For example, a method of applying a heat-shrinkable film to a polymer film and subjecting the polymer film to a stretching process or a shrinking process under the action of the shrinkage force by heating, or a method of obliquely aligning a liquid crystal polymer, And the like.

  Next, an example of a polarizing plate in which a viewing angle compensation film is further laminated on the polarizing plate of the first example will be described.

The viewing angle compensation film is a film for widening the viewing angle so that an image can be seen relatively clearly even when the screen of the liquid crystal display device is viewed not in a direction perpendicular to the screen but in a slightly oblique direction. As such a viewing angle compensation film, for example, a film obtained by coating a discotic liquid crystal on a triacetyl cellulose film or the like, or a retardation plate is used. As a normal retardation plate, for example, a uniaxially stretched in the plane direction, a polymer film having birefringence is used, while as the viewing angle compensation film, for example, biaxially stretched in the plane direction Retardation of bidirectionally stretched polymer film such as a polymer film having birefringence or a biaxially stretched film such as a uniaxially stretched film in a plane direction and also a film stretched in a thickness direction and having a controlled refractive index in a thickness direction. A board is used. Examples of the inclined alignment film include, for example, a film obtained by bonding a heat shrinkable film to a polymer film and subjecting the polymer film to a stretching treatment or a shrinking treatment under the action of the contraction force by heating, or a liquid crystal polymer obliquely oriented. And the like. In addition, as the raw material of the polymer film, the same material as the polymer material of the retardation plate extended above can be used.

Next, an example of a polarizing plate in which a brightness enhancement film is further laminated on the polarizing plate of the first example will be described.

偏光 This polarizing plate is usually used by being arranged on the back side of a liquid crystal cell. The brightness enhancement film is, for example, a backlight of a liquid crystal display device or the like, and reflects natural polarized light or linearly polarized light of a predetermined polarization axis or circularly polarized light of a predetermined direction when natural light is incident thereon, and transmits other light. It shows the characteristics of Light from a light source such as a backlight is incident to obtain transmitted light in a predetermined polarization state, and light other than the predetermined polarization state is reflected without transmitting. The light reflected on the surface of the brightness enhancement film is further inverted through a reflector or the like provided on the rear side thereof, and re-entered on the brightness enhancement film, and a part or all of the light is transmitted as light of a predetermined polarization state. In addition to increasing the amount of light transmitted through the brightness enhancement film, the polarization film (polarizer) is supplied with polarized light that is hardly absorbed, thereby increasing the amount of light that can be used for liquid crystal image display and the like, thereby improving the brightness. Things. Without using the brightness enhancement film, when light is incident through the polarizer from the back side of the liquid crystal cell with a backlight or the like, light having a polarization direction that does not match the polarization axis of the polarizer is almost absorbed by the polarizer. And does not pass through the polarizer. That is, although it depends on the characteristics of the polarizer used, about 50% of the light is absorbed by the polarizer, and accordingly, the amount of light that can be used for liquid crystal image display and the like decreases, and the image becomes darker. The brightness enhancement film, light having a polarization direction as absorbed by the polarizer, without being incident on the polarizer, once reflected by the brightness enhancement film, further provided a reflector provided on the back side And then re-enter the brightness enhancement film. Then, the polarization direction of the light reflected and inverted between the two passes through only the polarized light having a polarization direction that can pass through the polarizer, and supplies the polarized light to the polarizer. The light can be efficiently used for displaying an image on the liquid crystal display device, and the screen can be brightened.

Further, a diffusion plate may be provided between the brightness enhancement film and the reflection layer or the like. In this case, the light in the polarization state reflected by the brightness enhancement film is directed to the reflection layer, but the diffuser provided uniformly diffuses the passing light, and at the same time, eliminates the polarization state and changes the non-polarization state. And That is, it returns to the original natural light state. The light in the non-polarized state, that is, the light in the natural light state is repeatedly directed to the reflection layer or the like, reflected through the reflection layer, passed through the diffusion plate again, and re-enters the brightness enhancement film. As described above, by providing the diffusion plate that returns to the original natural light state, for example, while maintaining the brightness of the display screen, simultaneously reducing unevenness in the brightness of the display screen and providing a uniform bright screen. Can be. Further, it is considered that the diffusion plate appropriately increases the number of repetitions of reflection of the first incident light, and can provide a uniform bright display screen in combination with the diffusion function of the diffusion plate.

  The brightness enhancement film is not particularly limited, for example, a multilayer thin film of a dielectric, such as a multilayer laminate of thin film having different refractive index anisotropy, transmitting linearly polarized light of a predetermined polarization axis, Other light that shows a characteristic of reflecting light can be used. Specifically, for example, D-BEF (trade name, manufactured by 3M) can be used. In addition, such as a cholesteric liquid crystal layer, especially an alignment film of cholesteric liquid crystal polymer, or a film in which the alignment liquid crystal layer is supported on a film substrate, reflects either left or right circularly polarized light and transmits other light. May be indicated. As such a film, for example, “PCF350” (trade name, manufactured by Nitto Denko Corporation), and “Transmax” (trade name, manufactured by Merck) can be used.

  Therefore, in the case of a brightness enhancement film of a type that transmits linearly polarized light having a predetermined polarization axis, for example, the transmitted light is directly incident on the polarization plate with the polarization axis aligned, thereby suppressing absorption loss by the polarization plate. In addition, the light can be efficiently transmitted. On the other hand, a brightness enhancement film that transmits circularly polarized light, such as a cholesteric liquid crystal layer, can be directly incident on the polarizer.However, from the viewpoint of suppressing absorption loss, the transmitted circularly polarized light is transmitted through a retardation film. It is preferable that the light is converted into linearly polarized light through the polarizing plate and is incident on the polarizing plate. In addition, a circularly polarized light can be converted into a linearly polarized light by using, for example, a 波長 wavelength plate as the retardation plate.

  A retardation plate that functions as a quarter-wave plate in a wide wavelength range such as a visible light region is, for example, a retardation layer that functions as a quarter-wave plate with respect to monochromatic light such as light having a wavelength of 550 nm, and other layers. It can be obtained by laminating a retardation layer exhibiting retardation characteristics (for example, a retardation layer functioning as a half-wave plate). Therefore, the retardation plate disposed between the polarizing plate and the brightness enhancement film may be a laminate including one or two or more retardation layers. Note that the cholesteric liquid crystal layer can also have a stacked structure in which two or three or more layers are stacked by combining those having different reflection wavelengths. Thus, a polarizing plate that reflects circularly polarized light in a wide wavelength range such as a visible light region can be obtained, and based on that, transmitted circularly polarized light in a wide wavelength range can be obtained.

  The various polarizing plates in the third example as described above may be, for example, an optical film in which the polarizing plate and two or three or more optical layers are laminated. Specifically, for example, a reflective elliptically polarizing plate or a semi-transmissive elliptically polarizing plate obtained by combining the above-mentioned reflective polarizing plate or semi-transmissive polarizing plate with a retardation plate can be used.

  As described above, an optical film in which two or more optical layers are laminated can be formed, for example, by a method of sequentially and separately laminating in a manufacturing process of a liquid crystal display device or the like. However, there is an advantage that, for example, the stability of quality and the workability of assembling are excellent, and the manufacturing efficiency of a liquid crystal display device or the like can be improved. In addition, various bonding means, such as an adhesive layer, can be used for lamination similarly to the above.

  Each layer such as a polarizing film, a transparent protective layer, an optical layer and a pressure-sensitive adhesive layer forming the optical film of the present invention as described above is, for example, a salicylate compound, a benzophenone compound, a benzotriazole compound, a cyanoacrylate compound. Alternatively, those having an ultraviolet absorbing ability by appropriately treating with an ultraviolet absorbing agent such as a nickel complex compound may be used.

  Next, the liquid crystal panel of the present invention includes at least one of the polarizer and the optical film of the present invention (hereinafter, also referred to as “optical film”), which is disposed on at least one surface of the liquid crystal cell.

  The type of the liquid crystal cell is not particularly limited, and a conventionally known liquid crystal cell can be appropriately used. However, the polarizer and the like of the present invention are useful for a liquid crystal display device that displays light by causing polarized light to enter the liquid crystal cell. For this reason, among others, for example, a liquid crystal cell using a TN (Twisted Nematic) liquid crystal or an STN (Super Twisted Nematic) liquid crystal is preferable. In addition to these, a liquid crystal cell of IPS (In-Plane Switching), VA (Vertical Aligned), OCB (Optically Compensated Birefringence) mode using a non-twist type liquid crystal, or the dichroic dye is incorporated in the liquid crystal. It can also be used for a liquid crystal cell using a dispersed guest-host liquid crystal or a ferroelectric liquid crystal. Note that there is no particular limitation on the driving method of the liquid crystal.

  The optical film such as the polarizing plate may be disposed on only one surface of the liquid crystal cell, or may be disposed on both surfaces. When the optical films are arranged on both surfaces, the types of the optical films may be the same or different. When a polarizing plate or an optical member is provided on both sides of the liquid crystal cell, they may be the same or different.

  Further, ordinary components such as a prism array sheet, a lens array sheet, and a light diffusion plate may be provided at appropriate positions, and one or more of these components may be arranged.

  3 to 5 show examples of a liquid crystal panel on which the optical film of the present invention is arranged. These figures are cross-sectional views showing the state of lamination of a liquid crystal cell and an optical film, and are hatched to distinguish components. In the respective drawings, the same parts are denoted by the same reference numerals. Note that the liquid crystal panel of the present invention is not limited to these.

  The liquid crystal panel of FIG. 3 has a liquid crystal cell 12 and a polarizing plate 11, and the polarizing plates 11 are arranged on both surfaces of the liquid crystal cell 12, respectively. The structure (not shown) of the liquid crystal cell is not particularly limited, and is generally a structure in which liquid crystal is held between an array substrate and a filter substrate.

  The liquid crystal panel of FIG. 4 includes a liquid crystal cell 12, a polarizing plate 11, and a retardation plate 13, and the polarizing plates 11 are laminated on both surfaces of the liquid crystal cell 12 with the retardation plate 13 interposed therebetween. Note that the retardation plate 13 and the polarizing plate 11 may be disposed on both surfaces of the liquid crystal cell 12 as an integrated optical film of the present invention.

  The liquid crystal panel shown in FIG. 5A includes a liquid crystal cell 12, a polarizing plate 11, and a polarization conversion element 14. The polarizing plates 11 are laminated on both surfaces of the liquid crystal cell 12, respectively. The elements 14 are stacked. As the polarization conversion element 14, the above-described element can be used. For example, as shown in FIG. 1B, a composite of a quarter-wave plate 15 and a cholesteric liquid crystal 16 or the same in FIG. The anisotropic multiple thin film reflective polarizing element 17 shown in FIG. Note that the polarizing plate 11 and the polarization conversion element 14 may be disposed on one surface of the liquid crystal cell 12 as an integrated optical film of the present invention.

  Next, a liquid crystal display device of the present invention is a liquid crystal display device including a liquid crystal panel, wherein the liquid crystal panel is the liquid crystal panel of the present invention.

  The liquid crystal display device may further include a light source. The light source is not particularly limited, but is preferably, for example, a planar light source that emits polarized light, because light energy can be used effectively.

  In the liquid display device of the present invention, for example, a diffusion plate, an anti-glare layer, an antireflection film, a protective layer or a protective plate is further disposed on an optical film (polarizing plate) on the viewing side, or a liquid crystal cell in a liquid crystal panel. A compensating retardation plate or the like may be appropriately disposed between the polarizing plate and the polarizing plate.

  Next, an electroluminescent (EL) display device of the present invention is a display device having at least one of the polarizer of the present invention and the optical film of the present invention. This EL device may be either an organic EL or an inorganic EL.

In recent years, in an EL display device, it has been proposed to use an optical film such as a polarizer or a polarizing plate together with a λ / 4 plate to prevent reflection from an electrode in a black state. The polarizer or the optical film of the present invention is particularly suitable for the case where any one of linearly polarized light, circularly polarized light or elliptically polarized light is emitted from the EL layer, or even when natural light is emitted in the front direction, This is very useful when the emitted light in the direction is partially polarized.

First, a general organic EL display device will be described. The organic EL display device generally has a light-emitting body (organic EL light-emitting body) in which a transparent electrode, an organic light-emitting layer, and a metal electrode are stacked in this order on a transparent substrate. The organic light emitting layer is a laminate of various organic thin films, for example, a laminate of a hole injection layer made of a triphenylamine derivative or the like and a light emitting layer made of a fluorescent organic solid such as anthracene, Various combinations such as a stacked body of a light emitting layer and an electron injection layer made of a perylene derivative or the like, and a stacked body of the hole injection layer, the light emitting layer, and the electron injection layer are given.

  In such an organic EL display device, by applying a voltage to the anode and the cathode, holes and electrons are injected into the organic light emitting layer, and the holes and electrons are recombined. The emitted energy emits light on the principle that it excites the phosphor and emits light when the excited phosphor returns to the ground state. The mechanism of the recombination of holes and electrons is the same as that of a general diode, and the current and the emission intensity show strong nonlinearity with rectification with respect to the applied voltage.

In the organic EL display device, at least one electrode is required to be transparent in order to extract light emitted from the organic light emitting layer. Therefore, the organic EL display device is usually formed of a transparent conductor such as indium tin oxide (ITO). A transparent electrode is used as the anode. On the other hand, in order to facilitate electron injection and increase luminous efficiency, it is important to use a material having a small work function for the cathode, and usually a metal electrode such as Mg-Ag or Al-Li is used.

In the organic EL display device having such a configuration, it is preferable that the organic light emitting layer is formed of, for example, an extremely thin film having a thickness of about 10 nm. This is because light is transmitted almost completely in the organic light emitting layer as in the case of the transparent electrode. As a result, when light is not emitted, light that enters from the surface of the transparent substrate, passes through the transparent electrode and the organic light emitting layer, and is reflected by the metal electrode exits to the surface of the transparent substrate again. Therefore, when viewed from the outside, the display surface of the organic EL display device looks like a mirror surface.

  The organic EL display device of the present invention includes, for example, an organic EL display device including a transparent electrode on a front surface side of the organic light emitting layer and the organic EL light emitting body including a metal electrode on a back surface side of the organic light emitting layer. The optical film of the present invention (such as a polarizing plate) is preferably disposed on the surface of the transparent electrode, and a λ / 4 plate is preferably disposed between the polarizing plate and the EL element. Thus, by arranging the optical film of the present invention, an organic EL display device has an effect of suppressing reflection of the outside world and improving visibility. Further, it is preferable that a retardation plate is further disposed between the transparent electrode and the optical film.

  Since the retardation plate and the optical film (such as a polarizing plate) have a function of, for example, polarizing light incident from the outside and reflected by the metal electrode, the mirror effect of the metal electrode is visually recognized by the polarizing function. It has the effect of not letting it. In particular, if a quarter-wave plate is used as the phase difference plate and the angle between the polarization direction of the polarizing plate and the phase difference plate is adjusted to π / 4, the mirror surface of the metal electrode is completely shielded. can do. That is, only linearly polarized light components of the external light incident on the organic EL display device are transmitted by the polarizing plate. The linearly polarized light is generally converted into elliptically polarized light by the retardation plate. In particular, when the retardation plate is a quarter-wave plate and the angle is π / 4, the linearly polarized light becomes circularly polarized light.

This circularly polarized light, for example, passes through a transparent substrate, a transparent electrode, an organic thin film, is reflected by a metal electrode, again passes through an organic thin film, a transparent electrode, a transparent substrate, and is again linearly polarized by the retardation plate. Become. And, since this linearly polarized light is orthogonal to the polarization direction of the polarizing plate, it cannot pass through the polarizing plate, and as a result, the mirror surface of the metal electrode can be completely shielded as described above. .

  Further, the in-house manufacturing method of the liquid crystal display device and the electroluminescence display device of the present invention includes the polarizer of the present invention, which includes a surface protective film on the display surface side, and an adhesive layer and a release layer on the opposite surface. And a step of bonding at least one of the optical films of the present invention to the display device immediately after chip cutting.

  Thus, according to the in-house manufacturing method of cutting the polarizer or the optical film and producing various display devices by consistently performing bonding to a liquid crystal cell or the like, for example, in order to detect a defective area, Measurements must be made immediately, and marking decisions must be made by setting limit samples or measuring inline. According to the manufacturing method of the present invention, the polarizer or the optical film of the present invention is marked on a portion not satisfying the above condition (1), and immediately after punching, is bonded to a liquid crystal panel or an EL display element to perform various displays. The device can be manufactured. In this way, the processes from punching, sorting, and bonding of the polarizer and optical film can be performed consistently, and the inspection time can be simplified, so that manufacturing is simplified and cost reduction is achieved. You can also plan. Note that, in-house generally refers to an integrated line from punching of a roll of a polarizing plate to inspection and bonding to a LCD.

  Next, the present invention will be further described with reference to the following Examples and Comparative Examples. Note that the present invention is not limited to only these examples.

  Based on the conditions shown in Table 1 below, the PVA film was subjected to a swelling treatment, a dyeing treatment, a cross-linking treatment, a stretching treatment, and a washing treatment to produce a polarizer, and further produced a polarizing plate using the above-described polarizer. . Then, the performance of the polarizer and the polarizing plate was evaluated. As the PVA film, a PVA film having a degree of polymerization of 2400 (manufactured by Kuraray Co., Ltd .; trade name: VF-PS # 7500; width: 600 mm) and a PVA film having a degree of polymerization of 2600 (manufactured by Nippon Gohsei; trade name: OPL @ M-7500; (Width 600 mm) was used. The type of PVA film used in each of the examples and comparative examples is shown in Table 1 below according to the degree of polymerization. Table 1 also shows the thickness and the thickness displacement of the PVA film (raw material).

A. Production of Polarizer (1) Swelling treatment The PVA film was subjected to a swelling treatment under the conditions shown in Table 1 below. Specifically, the PVA film was dipped in a water bath (swelling bath) and stretched. Table 1 below shows the immersion time, the temperature of the swelling bath, and the stretching ratio with respect to the length of the PVA film (raw material) before swelling. In addition, a guide roll was used to improve the drainage property in the swelling bath (the same applies hereinafter).

(2) Dyeing treatment The PVA film was pulled out of the swelling bath, immersed in an aqueous solution containing 0.03% by weight of iodine (dyeing bath), and further stretched. Table 1 below shows the immersion time, the temperature of the dyeing bath, and the draw ratio with respect to the length of the raw fabric.

(3) Crosslinking treatment The PVA film was pulled out of the dyeing bath, immersed in an aqueous solution containing boric acid and KI (crosslinking bath), and further stretched. Table 1 below shows the immersion time, the temperature of the crosslinking bath, the draw ratio with respect to the length of the raw fabric, the concentration of boric acid and the concentration of KI in the dyeing bath. Table 1 shows the immersion time in the crosslinking bath.

(4) Stretching The PVA film was pulled up from the crosslinking bath, immersed in an aqueous solution containing boric acid and KI (stretching bath), and further stretched. Table 1 below shows the immersion time, the temperature of the immersion bath, the stretching ratio with respect to the length of the raw fabric, the boric acid concentration and the KI concentration in the stretching bath. Table 1 shows the immersion time in the stretching bath (time used for stretching).

(5) Rinsing treatment The PVA film was taken out of the stretching bath, immersed in a KI aqueous solution (rinsing bath), and then washed with water. Table 1 below shows the KI concentration and the temperature of the washing bath in the washing bath.

(6) Drying treatment The PVA film after the water washing treatment was dried at 25 ° C. for 3 minutes to obtain a polarizer. With respect to the width and thickness of the obtained polarizer, a layer pair value (%) when the width of the raw material was 100% and a relative value (%) when the thickness of the raw material was 100% were determined. . The results are shown in Table 1.

　Ｂ．偏光板の作製
　予め、商品名KC4UVX2MW（コニカフィルム社製）のTACフィルムを、４０℃の５重量％ＮＡＯＨ水溶液に２分間浸漬し、３０℃の純水で１分間水洗し、さらに１００℃で２分間乾燥させすることによって、けん化処理を施した保護フィルム（厚み４０μｍ）を作製した。この保護フィルムについて位相差計（王子計測機器社製、商品名ＫＯＢＲＡ21ＡＤＨ）を用いて位相差を測定した結果、面内位相差は１ｎｍであり、厚み方向位相差は２７ｎｍであった（測定波長550ｎｍ）。前述の偏光子の両面に前記保護フィルムを３重量％ＰＶＡ水溶液によって貼り付け、乾燥処理（６５℃、５分）を施すことによって、偏光板を作製した。

B. Preparation of Polarizing Plate A TAC film (trade name: KC4UVX2MW, manufactured by Konica Film Co., Ltd.) was previously immersed in a 5% by weight aqueous solution of NAOH at 40 ° C. for 2 minutes, washed with pure water at 30 ° C. for 1 minute, and further washed at 100 ° C. for 2 minutes. A saponification-treated protective film (thickness: 40 μm) was prepared by drying for minutes. The protective film was measured for retardation using a retardation meter (trade name: KOBRA21ADH, manufactured by Oji Scientific Instruments). As a result, the in-plane retardation was 1 nm, and the retardation in the thickness direction was 27 nm (measuring wavelength 550 nm). ). The protective film was attached to both surfaces of the polarizer with a 3% by weight aqueous solution of PVA, and dried (65 ° C., 5 minutes) to prepare a polarizing plate.

C. Evaluation method of performance (1) Measurement of phase difference The in-plane phase difference of the polarizing plate was measured using KOBRA-31PR (trade name, manufactured by Oji Scientific Instruments) (measuring wavelength: 1000 nm). Specifically, a total of 12276 points were measured for a polarizing plate having a length of 250 mm and a width of 200 mm every 2 mm in the plane. These results are shown in Table 2 as a range of phase difference fluctuation of the polarizing plate.

Further, the above-described differential phase difference change amount (σ) was obtained by substituting the phase difference between adjacent measurement points into the following expression (the number of obtained change amounts n = 12054). In the following equation, d is 2 mm. These results are shown in Table 2 as the fluctuation range of the amount of change in the differential phase difference of the polarizer.

σ = ΔR / d
ΔR = R _i -R _{i + 1}
Further, among the obtained in-plane phase differences, the difference between the maximum phase difference and the minimum phase difference, and the distance between the measurement point indicating the minimum phase difference and the measurement point indicating the minimum phase difference were determined. The results are shown in Table 2 below.

(2) Measurement of transmittance Y measured by using a spectrophotometer (trade name: DOT-3C: manufactured by Murakami Color Research Laboratory) and subjected to luminosity correction using a 2 degree field of view (C light source) of JIS Z8701. Indicated by value.

(3) Measurement of degree of polarization The transmittance (H ₀ ) when two identical polarizing plates are overlapped so that their polarization axes are parallel and the transmittance (H ₉₀ ) when they are overlapped orthogonally. And the degree of polarization was determined from the following equation. Note that the parallel transmittance (H ₀ ) and the orthogonal transmittance (H ₉₀ ) are Y values corrected for visibility in the same manner as described above.

　（４）単体色相、平行色相、直交色相の測定
　積分球式分光透過率測定器（商品名ＤＯＴ−３Ｃ；村上色彩技術研究所製）を使用して、単体色相ａ、単体色相ｂ、平行色相ａ、平行色相ｂ、直交色相ａ、直交色相ｂを測定した。これらの結果を下記表２に示す。

(4) Measurement of simple hue, parallel hue, and orthogonal hue Using a integrating sphere type spectral transmittance measurement device (trade name: DOT-3C; manufactured by Murakami Color Research Laboratory), simple hue a, simple hue b, parallel hue a, parallel hue b, orthogonal hue a, and orthogonal hue b were measured. The results are shown in Table 2 below.

(5) Evaluation method of display unevenness The polarizing plates obtained in the examples and the comparative examples were cut into 25 cm square by 20 cm square, and an adhesive was applied to the surface (light source side) of the high contrast type IPS liquid crystal cell. Then, SEG1425DU (trade name, manufactured by Nitto Denko) was bonded to the other surface (viewing side) of the liquid crystal cell. The obtained liquid crystal panel was placed on various backlights (A to D) to be described later such that the polarizing plate on the light source side (the prepared polarizing plate) faced down. Then, on the viewing side of the liquid crystal panel, observation was made from a front direction (0 °) and an oblique direction (30 °, 60 °), and unevenness during black display was evaluated based on the following evaluation criteria. The results are shown in Table 3 below.

(Backlight A)
FIG. 6 is a cross-sectional view schematically showing the backlight A. As shown in the figure, this backlight 6 is provided with a cold cathode tube 26 and a lamp house 27 on a wedge-type light guide plate 22 having a printed back surface, a diffusion plate 21 on the upper surface, and a diffuse reflection plate on the lower surface. 23 were arranged respectively.

(Backlight B)
FIG. 7 is a cross-sectional view schematically showing the backlight B. As shown in the drawing, this backlight 7 has a laminated body of a cholesteric layer and a λ / 4 plate layer arranged on the backlight 6 shown in FIG. At this time, the laminate was arranged such that the cholesteric surface (16) was on the backlight 6 side and the λ / 4 plate (15) was on the viewer side. When the liquid crystal cell is arranged on the backlight 7 as described above, the amount of transmitted light is maximized. In addition, as the laminate of the cholesteric layer and the λ / 4 plate layer, a laminate obtained by removing only the polarizing plate portion from PCF400TEG (trade name, manufactured by Nitto Denko Corporation) was used.

(Backlight C)
FIG. 8 is a cross-sectional view schematically showing the backlight C. As shown in the drawing, the backlight 8 has an anisotropic multiple thin film reflective polarizer (trade name: DBEF; manufactured by 3M) 17 disposed on the backlight 6 shown in FIG. When the liquid crystal cell is arranged on the backlight 8 as described above, the amount of transmitted light is maximized.

(Backlight D)
FIG. 9A is a cross-sectional view schematically showing a backlight D, and FIG. 9B is a view schematically showing a partial outline of the above-mentioned (A). As shown in the figure, the backlight 9 is provided with a cold cathode tube 26 and a lamp house 27 on a wedge-type light guide plate 25 having a prism formed on a light exit surface, and a diffuse reflection plate 23 on the lower surface of the light guide plate 25. The prism sheet 24 is disposed on the upper surface of the light guide plate 25. The prism sheet 24 was disposed so that its prism face faced the prism face of the light guide plate 25, as shown in a partially enlarged view (B) of FIG. Then, the diffusion plate 21 is further disposed on the upper surface of the prism sheet 24.

(Evaluation criteria)
5: No display unevenness is observed. 4: Display unevenness is not seen at all under fluorescent lamp lighting, and unevenness is slightly visible in darkness (dark room). 3: Display unevenness is completely displayed under fluorescent lamp lighting. Unseen, and unevenness is visible in the dark (dark room) 2: Display unevenness is slightly visible under fluorescent lighting 1: Display unevenness is clearly visible under fluorescent lighting

　表２に示すように、比較例の偏光子は1000ｎｍにおける面内位相差の変動範囲が、950〜1350ｎｍの範囲外であるため、表３に示すように表示ムラの評価が劣る結果となった。これに対して、前記変動範囲が950〜1350ｎｍの範囲である実施例の偏光子によれば、これを用いた偏光板は表示ムラが抑制され、表示特性に優れる結果となった。以上の結果から、本発明の偏光子であれば、表示ムラが抑制された各種画像表示装置を得ることができる。

As shown in Table 2, in the polarizer of the comparative example, the fluctuation range of the in-plane retardation at 1000 nm was out of the range of 950 to 1350 nm. . On the other hand, according to the polarizer of the example in which the fluctuation range is in the range of 950 to 1350 nm, the polarizing plate using the polarizer suppressed display unevenness and resulted in excellent display characteristics. From the above results, with the polarizer of the invention, it is possible to obtain various image display devices in which display unevenness is suppressed.

As described above, according to the polarizer of the present invention, even when used as an optical film such as a polarizing plate in a liquid crystal panel or a liquid crystal display device, there is no display unevenness, and excellent display characteristics can be achieved. Further, according to the present invention, since the polarizer, the polarizing plate, and the like can be marked by in-line measurement, for example, an off-line process such as an appearance inspection or packing immediately after the polarizer is chip-cut becomes unnecessary, and a liquid crystal display device or the like is consistently provided. In-house manufacturing for bonding to an electroluminescent display device is possible. Thus, for example, the cost of the display device can be reduced, and the manufacturing process can be easily managed, so that the industrial value is great.

FIG. 2 is a cross-sectional view illustrating an example of the optical film of the present invention. It is sectional drawing which shows the other example of the optical film of this invention. It is sectional drawing which shows the example of the liquid crystal panel of this invention. It is sectional drawing which shows the other example of the liquid crystal panel of this invention. (A) is a sectional view showing still another example of the liquid crystal panel of the present invention, and (B) and (C) are partial sectional views of the above (A). FIG. 2 is a cross-sectional view illustrating an example of a backlight according to the embodiment of the present invention. It is sectional drawing of the other example of the backlight in the said Example. It is sectional drawing of the other example of the backlight in the said Example. (A) is a sectional view of still another example of the backlight in the embodiment, and (B) is a partial schematic view of (A).

Explanation of reference numerals

REFERENCE SIGNS LIST 1 polarizer 2 transparent protective layer 3 adhesive layer 10, 11, 20 polarizing plate 12 liquid crystal cell 13 retardation plate 14 polarization conversion element 15 quarter-wave plate 16 cholesteric liquid crystal layer 17 anisotropic multiple thin-film reflective polarizing element 21 Diffusion plate 22 Light guide plate 23 Reflection plate 24 Prism sheet 25 Light guide plate with prism

Claims (19)

A polarizer comprising a dichroic substance in a matrix, wherein the in-plane retardation is in a range of 950 to 1350 nm at a measurement wavelength that does not show absorption. 2. The polarizer according to claim 1, wherein, at the measurement wavelength that does not show the absorption, the differential phase difference change amount (σ) of the in-plane phase difference is in a range of −5 nm / mm to 5 nm / mm. At the measurement wavelength that does not show the absorption, the distance between the measurement site that shows the maximum value of the in-plane retardation and the measurement site that shows the minimum value is in the range of 10 mm or less or in the range of 100 mm or more, and the maximum value. The polarizer according to claim 1, wherein a difference from the minimum value (in-plane retardation variation) is less than 60 nm. The polarizer according to any one of claims 1 to 3, wherein the measurement wavelength is in a range of 800 to 1500 nm. The polarizer according to claim 4, wherein the measurement wavelength is 1000 nm. The polarizer according to any one of claims 1 to 5, wherein the matrix is a polymer film. The polarizer according to claim 6, wherein the polymer film is a polyvinyl alcohol film. The polarizer according to any one of claims 1 to 7, which is chip-cut. An optical film comprising the polarizer according to claim 1. The optical film according to claim 9, further comprising a transparent protective layer, wherein the transparent protective layer is disposed on at least one surface of the polarizer. The polarizing plate according to claim 9 or 10, wherein an adhesive layer is disposed on at least one outermost layer. The optical film according to any one of claims 9 to 11, further comprising at least one of a polarization conversion element and a retardation film. The optical film according to claim 12, wherein the polarization conversion element is an anisotropic reflection-type polarization element or an anisotropic scattering-type polarization element. A liquid crystal panel in which at least one of the polarizer according to any one of claims 1 to 8 and the optical film according to any one of claims 9 to 13 is disposed on at least one surface of a liquid crystal cell. A liquid crystal display device comprising the liquid crystal panel according to claim 14. The liquid crystal display device according to claim 15, further comprising a plane light source that emits polarized light. An image display device comprising at least one of the polarizer according to any one of claims 1 to 8 and the optical film according to any one of claims 9 to 13. The image display device according to claim 17, which is an electroluminescence display device. It is an in-house manufacturing method of an image display device according to claim 17, wherein at least one of the polarizer according to any one of claims 1 to 8 and the optical film according to any one of claims 9 to 13 is used. An in-house manufacturing method including a step of attaching one of the chips to the display device immediately after chip cutting.

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